Increased danger for earthquakes in California, USGS says

The U.S. Geological Survey has just released new earthquake maps that show California is at an increased danger for earthquakes.

"Roads closed, a lot of shaking, buildings damaged, people without food and water for a period of time, pretty consequential," said Bob Barminski, a geologist.

That's how Barminski describes what Californians could soon feel again. The newly-published USGS map shows how intensely the ground could shake from an earthquake in 50 years.

"Earthquakes are going to be occurring more frequently in the future than in the past, just in general terms in California," Barminski said.

Forty-two of the 50 states have some chance of experiencing some damage from ground shaking resulting from an earthquake.

Barminski, who has studied geology since the 1970s, said the reason for the new insight is buried faults. Because some haven't came up to the surface, they're often not discovered until much later.

"So you don't find out about these faults unless you do detailed studies or unless you have an earthquake. As you find these faults it's like a newly discovered fault so then that's one reason you can increase earthquake risk," he said.

Another reason is that as scientists study the faults, they may notice different characteristics that lead them to draw new conclusions.

"You can dig and do trenches in a fault zone and figure out how often that fault has generated earthquakes in the past and you can come up with the recurrence interval, like every 100 years or every 50 years, and so that changes every time they do these studies," Barminski said.